The invention relates to electric lamp units and lighting assemblies and particularly to such units and assemblies adapted for use in projection applications, e.g. motion pictures, slide film, and microfilm projectors.
Even more particularly, this invention relates to means for assuring precision alignment of these units and assmeblies within such projectors.
One of the critical factors affecting the efficient operation of motion picture, slide, microfilm, and similar projectors is the alignment of the projection lamps used therein. Most projection assemblies utilize at least one lamp unit, the function of which is to concentrate the majority of light output from the unit's electric lamp toward a film "gate" or similar opening within the projector and thereafter onto the respective film. Projection lamp units also normally include a reflector which is coaxially-oriented with the lamp's filament to facilitate the aforementioned light concentration. Errors in alignment of the lamp assembly usually result in insufficient illumination of the film, lack of uniform illumination, as well as focusing problems due to the mismatch between the concentrated light and lens system typically employed in most projectors.
Most of the above alignment errors occur as a result of vibration and other external forces which tend to displace the lamp unit. Repeated replacement of the lamp unit may also adversely affect alignment.
It is therefore believed that an electric lamp unit and assembly particularly adapted for use within projection applications and capable of maintaining consistent alignment between the unit or assembly and the projector's film gate, lens system, etc. would constitute an advancement in the art.